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New Form of Matter Melds Lasers, Superconductors
sterlingda writes "Physicists at the University of Pittsburgh have demonstrated a new form of matter that melds the characteristics of lasers and superconductors. The work introduces a new method of moving energy from one point to another as well as a low-energy means of producing a light beam like that from a laser. The new state is a solid filled with a collection of energy particles known as 'polaritons' that have been trapped and slowed using a technique similar to that used to produce a Bose-Einstein condensate. The work is published in the May 18 issue of Science (subscription required to read beyond the abstract)."
It didn't say in TFA - does anybody know how dense these polaritrons are in the superfluid? Being, apparently, energy efficient to create, I'm wondering if this would make a good energy storage device - something to run those electric cars, even. It's hard to conjecture without a clue about how tight they're packed in, though.
I'm also pleasantly surprised to read that Bell Labs is still doing basic science - urban legend was that went out with the AT&T breakup.
Oh, and if anybody from physorg.com is reading, there's a strange display thing going on where ", " is replaced by "-" (not even space emdash space) in many sentences, making clause boundries in the sentences appear awkwardly as pseudo-hyphenated words.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
This business with polaritons in semiconductors sounds a lot like the way phonons in crystal lattices work.
A phonon is a sort of derived particle. It isn't a fundamental particle in itself but it represents a quantized mode of vibration in a lattice of more fundamental particles. But as a quasiparticle it exhibits the same types of behavior as other particles subject to quantum mechanics.
Their classical analogue would be standing waves in a crystal lattice. These lose part of their classical wave-like character and become more particle-like when the vibrational energy in the crystal decreases to near zero. The vibrational energy at extremely low temperatures takes the form of a few phonons bouncing around in the crystal like free particles in a hollow box. Phonons are ultimately responsible for all conduction of sound and heat through solids.
A polariton is apparently the coupling of a photon with one of these, and they're claiming to have gotten interesting collective behavior. I'm not sure if this is a "new state of matter" but we may get some cool toys out of it.
Okay, I found this other article about this discovery, and thought it was pretty good. It's worth a read:
http://physicsweb.org/articles/news/11/5/17/1
So this thing is like a BEC, but it's made of "excitons" (electron-hole pairs) plus the photons causing the excitation. But these "polaritons" are so short-lived, I'm wondering what this invention could be practically used for. They're calling it a "quasi-equilibrium" system, because it's more of a dynamic equilibrium.
Could this "polariton condensate" be used to probe "quantum foam", or spacetime, or something? They've already said it's more energy efficient than a laser.
Surely something this exotic must be able to confer on us some useful ability, that it would have some practical application -- even if only for research purposes.
When I think of an exciton-photon combination as compared to electron inversion, then it reminds me of the difference between a turbine and a piston engine. This "polariton" thingy (exciton-photon combo) would be more efficient than the laser in a way that's analogous to how the turbine is more efficient than the piston explosion. I'd think that the key to maximizing its advantage is by stimulating the excitons with the highest energy photons possible. That way you're maximizing your energy savings from this more efficient process.
Hmm... so maybe it might be useful for laser-confinement fusion after all. Maybe it could be used for laser-based rapid-manufacturing, etc.
Whatever it is, you'd probably want it for a short-range application, due to the brief lifespan of the polaritons.
Or, then again, maybe they won't find that new particles fit neatly with what has been established. Theoretical physicists have been trying to unify everything for the last 150 years - the current popular attempt is called string theory. It's not doing so well in the realm of "making useful or even testable predictions," though.
Ewige Blumenkraft.
No, they meant with the properties of a laser [beam]. The polaritons are coherent when they're confined, just* like photons are coherent in a laser beam.
Using specially designed optical structures with nanometer-thick layers-which allow polaritons to move freely inside the solid-Snoke and his colleagues captured the polaritons in the form of a superfluid. In superfluids and in their solid counterparts, superconductors, matter consolidates to act as a single energy wave rather than as individual particles.I suppose saying "beam" or talking about the photons in the laser beam would have been slightly more clear to the people who didn't read the article, but it's hardly something poorly written enough to be complaining about.
IAA physicist and material scientist, but I don't know enough about superconductors to really make worthwhile comments on that analogy. However, I am under the impression that the electrons pair up to form bosons that are then able to occupy the same energy levels and become coherent whereas normal electrons are fermions and can't do that.
* horrible, horrible use of the word "just"Guys, "Homeless" here *does not know what he is talking about*. Please stop modding him up. Both fermions and bosons are quantum fields (i.e. wave or particles but neither really), but their properties are vastly different for reasons that a real physicist IS taught in 1st year undergrad - The difference between spin odd-integer/2 and spin integer fields is vitally important and fundamental to physics. The ONLY KNOWN WAY to transform bosons into fermions at a fundamental level (as opposed to by mere aggregation - obviously even numbers of fermions together can act as pseudobosons, or by dimensional reduction - as in the weird fractional quantum hall effect that affects quantum systems confined to 2D) is via a "supersymmetry transformation", a so-far-only-theoretical construct.
Pretty sure. After all, cosmic rays produce collisions more energetic than those in any particle accelerator, so if the accelerators could produce any micro black holes capable of swallowing up the Earth, the sun would have got there first. Demonstrably, we're not inside an event horizon, so there you go.
Hi, I want to explain something here. This thing produces normal lasers, that are the same as the lasers we already know and love. The difference is that it can produce them using much less power input. The traditional method of electron population inversion requires more energy input for the amount of laser beam you get out. This new polariton method can make the same amount of laser for less energy inputted.
For laser-confinement fusion, you'd want that kind of energy savings.
Or SDI, or that ballistic missile interception laser mounted on that Boeing aircraft.
I'm even wondering if those desktop particle accelerators based on laser-wakefield effect wouldn't also benefit.
Anything that requires a high-power laser beam could benefit from this new polariton laser method. A turbine is already going round and round like a polariton, and is distinct from the discrete reciprocating motion of a piston, or the population inversion of electrons.
Okay, I know -- here's a good application:
http://www.mcp-group.com/rpt/rpttslm.html
Selective Laser Melting. It's a relatively new rapid prototyping technology which uses laser beams to melt powdered metal or plastic, so that it can be formed layer-by-layer into 3D parts.
So this would be an example of what this polariton laser would be good for, because the polaritons can generate the laser much more efficiently than conventional electron population inversion. Your power requirements would be reduced by 90%, and possibly even more.